We propose the development of a high fidelity flow sensor to continuously monitor tracheal gas flow in infants and young children who require a tracheostomy tube for relief of airway obstruction or chronic respiratory failure. An increasing number of children are surviving life threatening emergencies and acute respiratory failure or highly complex surgery; however, a growing number of these children subsequently require a tracheostomy for months or even years. Many of these children breathe through their tracheostomy tubes spontaneously and unassisted at all times, or for some hours of each day when not attached to a ventilator. The proposed sensor is specifically designed to monitor gas flow while the patient is not connected to the ventilator. The major hazard for such children at home or in special care/sub-acute facilities are life threatening incidents due to occlusion and/or extubation, which may result in rapid hypoxia with devastating brain damage or death. Each of the current monitoring techniques, including capnography, pulse oximetry, or impedance pneumograpy has certain problems and limitations. They all require that the child's sensors be connected by tubes or wires to an alarm system, which severely restricts mobility and are easily disconnected or disabled by the child. The long-term objective is to develop a system that will consist of a high-fidelity piezoelectric gas flow sensor, signal conditioner and a telemetry unit for data transmission and alarms so that the patient's mobility is not constrained. It will be based on an innovative piezoelectric sensor technology that is sensitive to extremely small changes in gas flow amplitude and direction. This technology will be used to develop and commercialize a small, reliable and inexpensive system. During Phase I of the project we propose to test the feasibility of this approach by designing and building a prototype of the sensor system; designing and constructing a prototype of a dedicated electronic circuitry and bench test the system under typical pulmonary flows anticipated in children with a tracheostomy. The availability of a very small, lightweight, accurate, rugged detector that could be attached to the tracheostomy tube connector to monitor inspiratory and expiratory gas flow, and alert the caregiver to impairment or cessation of gas flow would provide a measure of safety and efficacy not currently available.